gdb/python/py-function.c

   1 /* Convenience functions implemented in Python.
   2
   3    Copyright (C) 2008-2021 Free Software Foundation, Inc.
   4
   5    This file is part of GDB.
   6
   7    This program is free software; you can redistribute it and/or modify
   8    it under the terms of the GNU General Public License as published by
   9    the Free Software Foundation; either version 3 of the License, or
  10    (at your option) any later version.
  11
  12    This program is distributed in the hope that it will be useful,
  13    but WITHOUT ANY WARRANTY; without even the implied warranty of
  14    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  15    GNU General Public License for more details.
  16
  17    You should have received a copy of the GNU General Public License
  18    along with this program.  If not, see <http://www.gnu.org/licenses/>.  */
  19
  20
  21 #include "defs.h"
  22 #include "value.h"
  23 #include "python-internal.h"
  24 #include "charset.h"
  25 #include "gdbcmd.h"
  26 #include "cli/cli-decode.h"
  27 #include "completer.h"
  28 #include "expression.h"
  29 #include "language.h"
  30
  31 extern PyTypeObject fnpy_object_type
  32     CPYCHECKER_TYPE_OBJECT_FOR_TYPEDEF ("PyObject");
  33
  34 \f
  35
  36 /* Return a reference to a tuple ARGC elements long.  Each element of the
  37    tuple is a PyObject converted from the corresponding element of ARGV.  */
  38
  39 static gdbpy_ref<>
  40 convert_values_to_python (int argc, struct value **argv)
  41 {
  42   int i;
  43   gdbpy_ref<> result (PyTuple_New (argc));
  44
  45   if (result == NULL)
  46     return NULL;
  47
  48   for (i = 0; i < argc; ++i)
  49     {
  50       gdbpy_ref<> elt (value_to_value_object (argv[i]));
  51       if (elt == NULL)
  52         return NULL;
  53       PyTuple_SetItem (result.get (), i, elt.release ());
  54     }
  55   return result;
  56 }
  57
  58 /* Call a Python function object's invoke method.  */
  59
  60 static struct value *
  61 fnpy_call (struct gdbarch *gdbarch, const struct language_defn *language,
  62            void *cookie, int argc, struct value **argv)
  63 {
  64   /* The gdbpy_enter object needs to be placed first, so that it's the last to
  65      be destroyed.  */
  66   gdbpy_enter enter_py (gdbarch, language);
  67   struct value *value;
  68   gdbpy_ref<> result;
  69   gdbpy_ref<> args = convert_values_to_python (argc, argv);
  70
  71   /* convert_values_to_python can return NULL on error.  If we
  72      encounter this, do not call the function, but allow the Python ->
  73      error code conversion below to deal with the Python exception.
  74      Note, that this is different if the function simply does not
  75      have arguments.  */
  76
  77   if (args != NULL)
  78     {
  79       gdbpy_ref<> callable (PyObject_GetAttrString ((PyObject *) cookie,
  80                                                     "invoke"));
  81       if (callable == NULL)
  82         error (_("No method named 'invoke' in object."));
  83
  84       result.reset (PyObject_Call (callable.get (), args.get (), NULL));
  85     }
  86
  87   if (result == NULL)
  88     gdbpy_handle_exception ();
  89
  90   value = convert_value_from_python (result.get ());
  91   if (value == NULL)
  92     {
  93       gdbpy_print_stack ();
  94       error (_("Error while executing Python code."));
  95     }
  96
  97   return value;
  98 }
  99
 100 /* Initializer for a Function object.  It takes one argument, the name
 101    of the function.  */
 102
 103 static int
 104 fnpy_init (PyObject *self, PyObject *args, PyObject *kwds)
 105 {
 106   const char *name;
 107   gdb::unique_xmalloc_ptr<char> docstring;
 108
 109   if (! PyArg_ParseTuple (args, "s", &name))
 110     return -1;
 111
 112   gdbpy_ref<> self_ref = gdbpy_ref<>::new_reference (self);
 113
 114   if (PyObject_HasAttrString (self, "__doc__"))
 115     {
 116       gdbpy_ref<> ds_obj (PyObject_GetAttrString (self, "__doc__"));
 117       if (ds_obj != NULL)
 118         {
 119           if (gdbpy_is_string (ds_obj.get ()))
 120             {
 121               docstring = python_string_to_host_string (ds_obj.get ());
 122               if (docstring == NULL)
 123                 return -1;
 124             }
 125         }
 126     }
 127   if (! docstring)
 128     docstring.reset (xstrdup (_("This function is not documented.")));
 129
 130   add_internal_function (make_unique_xstrdup (name), std::move (docstring),
 131                          fnpy_call, self_ref.release ());
 132   return 0;
 133 }
 134
 135 /* Initialize internal function support.  */
 136
 137 int
 138 gdbpy_initialize_functions (void)
 139 {
 140   fnpy_object_type.tp_new = PyType_GenericNew;
 141   if (PyType_Ready (&fnpy_object_type) < 0)
 142     return -1;
 143
 144   return gdb_pymodule_addobject (gdb_module, "Function",
 145                                  (PyObject *) &fnpy_object_type);
 146 }
 147
 148 \f
 149
 150 PyTypeObject fnpy_object_type =
 151 {
 152   PyVarObject_HEAD_INIT (NULL, 0)
 153   "gdb.Function",                 /*tp_name*/
 154   sizeof (PyObject),              /*tp_basicsize*/
 155   0,                              /*tp_itemsize*/
 156   0,                              /*tp_dealloc*/
 157   0,                              /*tp_print*/
 158   0,                              /*tp_getattr*/
 159   0,                              /*tp_setattr*/
 160   0,                              /*tp_compare*/
 161   0,                              /*tp_repr*/
 162   0,                              /*tp_as_number*/
 163   0,                              /*tp_as_sequence*/
 164   0,                              /*tp_as_mapping*/
 165   0,                              /*tp_hash */
 166   0,                              /*tp_call*/
 167   0,                              /*tp_str*/
 168   0,                              /*tp_getattro*/
 169   0,                              /*tp_setattro*/
 170   0,                              /*tp_as_buffer*/
 171   Py_TPFLAGS_DEFAULT | Py_TPFLAGS_BASETYPE, /*tp_flags*/
 172   "GDB function object",          /* tp_doc */
 173   0,                              /* tp_traverse */
 174   0,                              /* tp_clear */
 175   0,                              /* tp_richcompare */
 176   0,                              /* tp_weaklistoffset */
 177   0,                              /* tp_iter */
 178   0,                              /* tp_iternext */
 179   0,                              /* tp_methods */
 180   0,                              /* tp_members */
 181   0,                              /* tp_getset */
 182   0,                              /* tp_base */
 183   0,                              /* tp_dict */
 184   0,                              /* tp_descr_get */
 185   0,                              /* tp_descr_set */
 186   0,                              /* tp_dictoffset */
 187   fnpy_init,                      /* tp_init */
 188   0,                              /* tp_alloc */
 189 };